Demetallization and desulfurization of heavy oil residues by adsorbents

The purpose of the work is demetallization and desulfurization of heavy oil residues using adsorbents. Optimal parameters of the demetallization and desulfurization processes of heavy vacuum fraction of Pavlodar Petrochemical Plant LLP in the presence of a zeolite adsorbent containing vanadium oxide xerogel were established: temperature 340?°C, pressure 1?atm., bulk feed rate 1?h^?1. As a result of the process the extraction degree of vanadium, nickel and iron were 90, 70 and 60%, respectively, and the sulfur content decreased from 1.97 to 1.36%. Composition of the chemical adsorbent for demetallization and desulfurization of heavy vacuum fraction is established, too. Content of vanadium, iron and sulfur increase in composition of the adsorbent after treatment of heavy vacuum fraction, which confirms its high adsorption capacity regarding to metals and sulfur.     

Effects of SiC whisker addition on mechanical,thermal, and permeability properties of porous silica-bonded SiC ceramics

The effects of SiC whisker addition into nano-SiC powder-carbon black template mixture on flexural strength, thermal conductivity, and specific flow rate of porous silica-bonded SiC ceramics were investigated. The flexural strength of 1200°C-sintered porous silica-bonded SiC ceramics increased from 9.5 MPa to 12.8 MPa with the addition of 33 wt% SiC whisker because the SiC whiskers acted as a reinforcement in porous silica-bonded SiC ceramics. The thermal conductivity of 1200°C-sintered porous silica-bonded SiC ceramics monotonically increased from 0.360 Wm^–1K^–1 to 1.415 Wm^–1K^–1 as the SiC whisker content increased from 0 to 100 wt% because of the easy heat conduction path provided by SiC whiskers with a high aspect ratio. The specific flow rate of 1200°C-sintered porous SiC ceramics increased by two orders of magnitude as the SiC whisker content increased from 0 to 100 wt%. These results were primarily attributed to an increase in pore size from 125 nm to 565 nm and secondarily an increase in porosity from 49.9% to 63.6%. In summary, the addition of 33 wt% SiC whisker increased the flexural strength, thermal conductivity, and specific flow rate of porous silica-bonded SiC ceramics by 35%, 133%, and 266%, respectively.     

Crystal Structure and Thermodynamic Properties of Barium–Thulium Bismuthate with Perovskite Structure

A new sample of triple oxides—barium–thulium bismuthate Ba₂TmBiO₆ with perovskite structure—has been synthesized by ceramic technology. The unit cell parameters of the sample and the coefficients of thermal expansion have been determined by the method of X‐ray analysis. Thermal properties of the sample have been studied by DTA over the temperature range of 293–1473 K. The heat capacity of the compound has been measured over the range of 5–320 K by vacuum adiabatic calorimetry. Thermodynamic functions of the compound have been determined based on the heat capacity data.     

Electrical,thermal, and mechanical properties of porous silicon carbide ceramics with a boron carbide additive

The effects of the boron carbide (B₄C) content and sintering atmosphere on the electrical, thermal, and mechanical properties of porous silicon carbide (SiC) ceramics were investigated in the porosity range of 58.3%–70.3%. The electrical resistivities of the nitrogen-sintered porous SiC ceramics (∼10^–1 Ω·cm) were two orders of magnitude lower than those of argon-sintered porous SiC ceramics (∼10¹ Ω·cm). Both the thermal conductivities (3.3–19.8 W·m^–1·K^–1) and flexural strengths (8.1–32.9 MPa) of the argon- and nitrogen-sintered porous SiC ceramics increased as the B₄C content increased, owing to the decreased porosity and increased necking area between SiC grains. The electrical resistivity of the porous SiC ceramics was primarily controlled by the sintering atmosphere owing to the N-doping from the nitrogen atmosphere, and secondarily by the B₄C content, owing to the B-doping from the B₄C. In contrast, the thermal conductivity and flexural strength were dependent on both the porosity and necking area, as influenced by both the sintering atmosphere and B₄C content. These results suggest that it is possible to decouple the electrical resistivity from the thermal conductivity by judicious selection of the B₄C content and sintering atmosphere.